The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
It is known to provide an exhaust system for an engine with an emission treatment device. For instance, an engine may include an exhaust system equipped with a diesel particulate filter (“DPF”), a diesel oxidation catalyst (“DOC”), a selective catalytic reduction (“SCR”) device, and/or a three way catalyst (“TWC”). These emission treatment devices reduce the amount of undesirable materials flowing with the exhaust gases.
More specifically, a diesel particulate filter typically receives exhaust flowing from the combustion chambers of the engine and collects soot contained therein. Periodically, the diesel particulate filter undergoes a process called regeneration to reduce and remove the collected soot. Regeneration can be performed passively (with a catalyst that is added to the filter) or actively (by controlling the engine to increase exhaust temperature, using a fuel burner to increase the exhaust temperature, injecting fuel into the exhaust stream, etc.).
Typically, the engine includes a plurality of combustion chambers, and exhaust from each chamber flows into a manifold, which directs flow of the combined exhaust gases into a single exhaust treatment device. However, in this configuration, a significant amount of input energy is needed to increase exhaust temperature. Also, a relatively large exhaust treatment device is needed, and as such, it may be difficult to provide adequate space within the vehicle for the exhaust treatment device.
In another configuration, the exhaust system includes a plurality of exhaust treatment devices. Each exhaust treatment device is fluidly coupled to a separate combustion chamber. As such, exhaust gas from each combustion chamber flows separately to a different exhaust treatment device. However, this type of system is relatively complex, includes a substantial number of components, and can be relatively expensive.